00:00
In this talk, we're going to discuss spinal cord disorders.
This is a really important talk.
00:07
We see a lot of different presentations from spinal cord
pathology but if you can
break it down and figure out where in the spinal cord the
problem is, it becomes much
easier to approach these patients in either a case or a
question. So let's start with an
introduction to spinal cord disorders and diseases, and
let's begin with a case. This is a
45-year-old who awoke with bilateral lower extremity
weakness and numbness which
resolved over several days. Over the next few weeks, he
developed back pain and
gradually progressive urinary retention and constipation.
Lumbar spine MRI showed mild
degenerative changes and he subsequently developed genital
numbness and sexual
dysfunction. Inflammatory myopathy was initially suspected
and corticosteroids were
administered, but within 12 hours he suddenly developed
bilateral paraparesis
meaning weakness and numbness below the waist and severe
worsening of his
symptoms. Exam now shows 2/5 strength in the bilateral lower
extremities. He can't
achieve at least antigravity strength in the legs;
hyperreflexia in the bilateral lower
extremities; and bilateral Babinski signs, evidence of upper
motor neuron dysfunction.
01:25
Sensory exam shows reduced pinprick, temperature, and
vibration in the legs. Upper
extremity examination is normal. So let's walk through some
of the key features
of this case that guide us to where the problem is and what
the localization is for this
patient. The first is the strength exam. This patient has
significant bilateral relatively
symmetric weakness in the legs. That's a paraparesis or
weakness and often numbness
below the waist, and this is strongly indicative of a spinal
cord disorder. The 2nd
is the reflex exam, which is really important in this case.
Reflexes are some of the most
objective portions of our exam and here the presence of
bilateral hyperreflexia points
to an upper motor neuron disorder and squarely sets this in
the spinal cord. The last
is the sensory exam and we have diffuse sensory dysfunction
to pain and temperature
with pinprick and temperature reduction as well as vibration
and proprioception with
reduced vibration in the bilateral legs. And we really want
to interrogate in this patient
whether there is a sensory level, which would also be
supportive of a spinal cord
disorder. And the last is a unique wildcard in this case,
which is very rare, and must be
something to focus in on when you see it, and this patient
had sudden worsening
of symptoms with initiation of corticosteroids. Steroids are
one of those medicines
we use in neurology and medicine to help just about any
problem. They can help
inflammatory disorders and some infectious disorders, and in
paraneoplastic disorders
but there is dramatic worsening in this patient with the
initiation of steroids and this
tips us off that this may be vascular in origin. So, what's
the localization? Where is this
problem? Is it in the brain, the subcortex, brainstem, or
spinal cord? Well, this isn't a
presentation of a brain disorder. There's no cortical
symptoms, no abnormality in
mental status. The mental status exam was essentially normal
and not mentioned
because of its normality in this patient and this is not the
presentation of brain
pathology. Similarly, there is nothing pointing us to
something in the subcortex.
03:35
The symptoms and deficits involved both legs, and the motor
and sensory fibers to the
legs are different, they're in opposite sides, opposite
hemispheres of the brain in the
subcortex. It would take a really large lesion to affect
both legs and the motor and
sensory fibers for both legs and we would surely see
problems with mentation or other
brain symptoms or signs in these patients and this is
inconsistent with the presentation
from the subcortex. We also don't see things that point us
to the brainstem. They're
not crossed findings or cranial nerve dysfunction and
nothing else that points us to
brainstem pathology. And this is the classic presentation of
someone with a myelopathy
or a spinal cord disorder. A paraparesis, upper motor neuron
reflexes, and the presence
of a sensory level would seal the deal on a myelopathic
process. In this patient,
the patient underwent MRI of the spine which is a critical
diagnostic test that we'll find in
evaluating these patients and here in A we're looking at a
T2 image and this shows
the spinal cord is dark and any pathology shows up is
bright. And we can see throughout
the thoracic spine there is increased signal hyperintensity,
white signal within the
spinal cord from, in this case, a venous hypertension. Some
pathology is present in the
spinal cord and that's what's causing this patient's
symptoms. In B, we're looking just
lateral to the spinal cord and we see this area of flow
void, dark signal within the spinal
fluid that is suggestive of an enlarged blood vessel. This
patient went on to have a spinal
angiogram, which you can see in C and D and we have a large
vein arising from an
artery, a medullary branching artery in to the spinal cord
and that vein is the problem.
05:17
It is a connection between the artery and a vein. It results
in venous hypertension
or back-up of blood within the venous flow of the spinal
cord, and that's what that
signal is so that we're seeing the spinal cord is venous
hypertension, too much blood
in the veins spilling into the spinal cord. And this is the
classic imaging of a spinal dural
AV fistula, which was the cause of this patient's chonical
symptoms and one of those
unique disorders that worsens with corticosteroid
administration.